1. Field of the Invention
The present invention relates to an exchange coupling film composed of an antiferromagnetic layer and a ferromagnetic layer, the magnetization direction of the antiferromagnetic layer being fixed along a prescribed direction due to an exchange anisotropic magnetic field generated at the interface between the antiferromagnetic layer and ferromagnetic layer. Especially, the present invention relates to an exchange coupling film being allowed to obtain a larger exchange anisotropic magnetic field when the antiferromagnetic layer is formed of an antiferromagnetic material containing an element X (for example, Pt or Pd) and Mn, and to a magnetoresistive element (spin-valve type thin film element; AMR (anisotropic magnetoresistive) element) using this exchange coupling film.
2. Description of the Related Art
The spin-valve type thin film element belongs to one of GMR (giant magnetoresistive) elements making use of a giant magnetoresistance effect for sensing recording magnetic field from a recording medium such as a hard disk unit.
This spin-valve type thin film element has a relatively simple construction among the GMR elements along with having some features that its resistance can be varied under a weak magnetic field.
The spin-valve type thin film element described above has a most simple construction composed of an antiferromagnetic layer, a pinned magnetic layer, a non-magnetic conductive layer and a free magnetic layer.
The antiferromagnetic layer is formed in direct contact with the pinned magnetic layer and the magnetization direction of the pinned magnetic layer is fixed along a prescribed direction forming a single magnetic domain due to the exchange anisotropic magnetic field generated at the interface between the antiferromagnetic layer and pinned magnetic layer.
Magnetization of the free magnetic layer is aligned along the direction to cross with the magnetization direction of the pinned magnetic layer by being affected by bias layers formed at both sides of the free magnetic layer.
Usually, a film of a Fexe2x80x94Mn (iron-manganese) alloy or Nixe2x80x94Mn (nickel-manganese) alloy is used for the antiferromagnetic layer, a film of a Nixe2x80x94Fe (nickel-iron) alloy is used for the pinned magnetic layer and free magnetic layer, a Cu (copper) film is used for the non-magnetic conductive layer 3 and a film of a Coxe2x80x94Pt (cobalt-platinum) alloy is used for the bias layer.
In this spin-valve type thin film element, electric resistance is changed depending on the direction of the pinned magnetic field of the pinned magnetic layer related to variation of the magnetization direction of the free magnetic field caused by leakage magnetic field from the magnetic medium such as a hard disk unit. The leakage magnetic field can be thus sensed from voltage changes ascribed to this electric resistance changes.
Although the films of the Fexe2x80x94Mn alloy or Nixe2x80x94Mn alloys are used for the antiferromagnetic layer as described above, the film of the Fexe2x80x94Mn alloy has drawbacks of low corrosion resistance, small exchange anisotropic magnetic field and a blocking temperature as low as about 150xc2x0 C. Low blocking temperature causes a problem that the exchange anisotropic magnetic field is quenched by the temperature increase of the element during the manufacturing process of the head or in the head under operation.
The film of the Nixe2x80x94Mn alloy has, on the contrary, a relatively large exchange anisotropic magnetic field as well as a blocking temperature of as high as about 300xc2x0 C. Therefore, it is preferable to use the film of the Nixe2x80x94Mn alloy rather than using the film of the Fexe2x80x94Mn alloy for the antiferromagnetic layer.
B. Y. Wong, C. Mitsumata, S. Prakash, D. E. Laughlin and T. Kobayashi (Journal of Applied Physics, vol. 79, No. 10, p. 7896-7904 (1996)) reported the interface structure between the antiferromagnetic layer and pinned magnetic layer (the film of the Nixe2x80x94Fe-alloy) when the film of the Nixe2x80x94Mn alloy is used for the antiferromagnetic layer in.
The report describes xe2x80x9cThe film grows by keeping a crystal coherency at the NiFe/NiMn interface so that both {111} planes of NiFe and NiMn are parallel to the film surface. Coherent strain at the interface is relaxed by introducing a large number of twins having twining planes parallel to the film surface. However, ordering of the NiMn in the vicinity of the interface is suppressed due to remaining interface strain, making the degree of order high at the site spaced apart from the interface.xe2x80x9d
The term xe2x80x9ccoherentxe2x80x9d refers to a state where atoms in the antiferromagnetic layer and pinned magnetic layer at the surface exist in 1:1 correspondence with each other and, conversely, the term xe2x80x9cincoherentxe2x80x9d refers to a state where atoms in the antiferromagnetic layer and pinned magnetic layer at the interface are not located to form respective pairs between the layers.
A heat treatment allows an exchange anisotropic magnetic field to generate at the interface between the NiMn alloy and pinned magnetic field when the antiferromagnetic layer is formed of the NiMn alloy, because the NiFe alloy is transformed from a disordered lattice to an ordered lattice by applying a heat treatment.
While the crystal structure of the NiMn alloy assumes a face centered cubic lattice in which Ni and Mn atoms are distributed at random prior to subjecting to the heat treatment, the crystal structure is transformed from the face centered cubic lattice to the face centered tetragonal lattice after the heat treatment with ordering of the atomic sites (referred to a ordered lattice hereinafter). The ratio (c/a) of the lattice constant a to the lattice constant c of the film of the Nixe2x80x94Mn alloy when the crystal structure is transformed into a perfectly ordered lattice is 0.942.
Since the lattice constant ratio c/a in the film of the MiMn alloy having a perfectly ordered lattice is relatively close to 1, the lattice strain at the interface generated during the modification from the disordered lattice to the ordered lattice becomes relatively small. Accordingly, the NiMn alloy is transformed from the disordered lattice to the ordered lattice by subjecting the alloy to a heat treatment even if the interface structure between the film of the NiMn alloy and the pinned magnetic layer assumes a coherent state, thereby generating an exchange anisotropic magnetic field.
The lattice strain at the interface is somewhat relaxed by forming twins, as described in the foregoing paper.
As hitherto described, the NiMn alloy has relatively large exchange anisotropic magnetic field as well as a blocking temperature of as high as 300xc2x0 C., exhibiting superior characteristics to the conventional FeMn alloys. However, the alloy is not sufficient with respect to corrosion resistance as in the FeMn alloys.
Accordingly, Xxe2x80x94Mn alloys (X=Pt, Pd, Ir, Rh, Ru and Os) using platinum group elements has been recently noticed for the antiferromagnetic material that is excellent in corrosion resistance along with being able to generate higher exchange anisotropic magnetic field and having a higher blocking temperature.
Using the Xxe2x80x94Mn alloy containing platinum group elements as the antiferromagnetic layer makes it possible to improve conventional reproduction output, besides substantially eliminating the drawbacks that the reproduction characteristics are deteriorated by quenching the exchange anisotropic magnetic field due to temperature increase of the element in the magnetic head under operation.
Meanwhile, a heat treatment after deposition is required, as in the case when the NiMn alloy is used for the antiferromagnetic layer, for allowing the exchange anisotropic magnetic field to generate when the Xxe2x80x94Mn alloy containing platinum group elements is used for the antiferromagnetic layer.
Although the foregoing paper describes that the interface structure between the NiMn alloy and the pinned magnetic layer (NiFe alloy) remains to be coherent, it was made clear that the exchange anisotropic magnetic field was hardly generated after the heat treatment when the interface structure with the pinned magnetic layer is made to be coherent as in the case of the Xxe2x80x94Mn alloy (X is a platinum element).
The present invention, which is provided to solve the foregoing problems in the prior art, is related to an exchange coupling film that is allowed to generate a large exchange anisotropic magnetic field when an antiferromagnetic material containing elements X (X corresponds to platinum group elements) and Mn is used for the antiferromagnetic layer, and to a megnetoresistive element using this exchange coupling film.
The present invention provides an exchange coupling film in which an antiferromagnetic layer is formed in direct contact with a ferromagnetic layer, an exchange anisotropic magnetic field is generated at the interface between the antiferromagnetic layer and ferromagnetic layer and the magnetization direction of the ferromagnetic layer is fixed along a prescribed direction, wherein the antiferromagnetic layer is formed of an antiferromagnetic material containing at least the element X (wherein X is either one or two or more of the elements Pt, Pd, Ir, Rh, Ru and Os) and Mn, the interface structure between the antiferromagnetic layer and the ferromagnetic layer being non-coherent.
It is preferable that at least a part of the crystal structure of the antiferromagnetic layer after the heat treatment assumes a L10 type face-centered tetragonal ordered lattice.
It is preferable that crystal orientation of the antiferromagnetic layer is different from the crystal orientation of the ferromagnetic layer at the interface between the antiferromagnetic layer and ferromagnetic layer.
The degree of orientation of the {111} plane of the antiferromagnetic layer is lower than the degree of orientation of the ferromagnetic layer or the plane is non-oriented in contrast to the {111} plane of the ferromagnetic layer being preferentially oriented along the direction parallel to the interface with the antiferromagnetic layer in the present invention.
Otherwise, the degree of orientation of the {111} plane of the ferromagnetic layer is lower than the degree of orientation of the antiferromagnetic layer or the plane is non-oriented in contrast to the {111} plane of the antiferromagnetic layer being preferentially oriented along the direction parallel to the interface with the ferromagnetic layer.
Otherwise, both of the degree of orientation of the {111} plane of the antiferromagnetic layer along the direction parallel to the interface between the antiferromagnetic layer and ferromagnetic layer and the degree of orientation of the {111} plane of the ferromagnetic layer are low or the both planes are non-oriented, the crystal planes except the {111} planes being preferentially oriented along the direction parallel to the interface with different crystal orientations between the antiferromagnetic layer and ferromagnetic layer.
It is preferable in the present invention that the antiferromagnetic layer is formed of a Xxe2x80x94Mn alloy and the element X is PT.
It is preferable that the ratio (c/a) of the lattice constant a to the lattice constant c of the antiferromagnetic layer after the heat treatment is within the range of 0.93 to 0.99 when the antiferromagnetic layer is formed of the PtMn alloy.
In the present invention, the antiferromagnetic layer is formed of a Xxe2x80x94Mnxe2x80x94Xxe2x80x2 alloy (wherein X is either one or two or more of the elements of Pt, Pd, Ir, Rh, Ru and Os), the Xxe2x80x94Mnxe2x80x94Xxe2x80x2 being an invasion type solid solution in which the element Xxe2x80x2 invades into interstices in the space lattice composed of the elements X and Mn, or a substitution type solid solution in which a part of the lattice points of the crystal lattice composed of the element X and Mn is substituted with the element Xxe2x80x2. It is especially preferable in the present invention that the element X in the Xxe2x80x94Mnxe2x80x94Xxe2x80x2 alloy to be used for the antiferromagnetic layer is Pt, or the antiferromagnetic layer is formed of a Ptxe2x80x94Mnxe2x80x94Xxe2x80x2 alloy.
It is preferable in the present invention that the element Xxe2x80x2 that is used for the antiferromagnetic layer is one or two or more kinds of the elements of Ne, Ar, Kr, Xe, Be, B, C, N, Mg, Al, Si, P, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ag, Cd, Ir, Sn, Hf, Ta, W, Re, Au, Pb and rare earth elements. It is more preferable that the element Xxe2x80x2 is one or two or more kinds of the elements of Ne, Ar, Kr and Xe.
It is preferable in the present invention that the composition ratio of the element Xxe2x80x2 is within the range of 0.2 to 10%, more preferably within the range of 0.5 to 5%, by atomic ratio when the antiferromagnetic layer is formed of a Xxe2x80x94Mnxe2x80x94Xxe2x80x2 alloy.
In addition, it is preferable in the present invention that the composition ratio (X:Mn) between the element X and Mn is within the range of 4:6 to 6:4 when the antiferromagnetic layer is formed of the Xxe2x80x94Mnxe2x80x94Xxe2x80x2 alloy.
The Xxe2x80x94Mnxe2x80x94Xxe2x80x2 alloy to be used for the antiferromagnetic layer is preferably deposited by the sputtering method.
The antiferromagnetic layer is formed of a Xxe2x80x94Mn alloy (wherein X is either one or two or more of the elements of Pt, Pd, Ir, Rh, Ru and Os), and it is preferable that the antiferromagnetic layer is formed on the ferromagnetic layer with the composition ratio of X in the Xxe2x80x94Mn alloy of within the range of 47 to 57% by atomic ratio.
The antiferromagnetic layer is formed of the Xxe2x80x94Mnxe2x80x94Xxe2x80x2 alloy (wherein X is either one or two or more of the elements of Pt, Pd, Ir, Rh, Ru and Os and Xxe2x80x2 is one or two or more kinds of the elements of Ne, Ar, Kr, Xe, Be, B, C, N, Mg, Al, Si, P, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ag, Cd, Ir, Sn, Hf, Ta, W, Re, Au, Pb and rare earth elements) in the present invention, wherein the antiferromagnetic layer is formed over the ferromagnetic layer and it is preferable that the composition ratio of X+Xxe2x80x2 in the Xxe2x80x94Mnxe2x80x94Xxe2x80x2 alloy is within the range of 47 to 57% by atomic ratio.
It is more preferable in the present invention that the composition ratio of X in the Xxe2x80x94Mn alloy or the composition ratio of X+Xxe2x80x2 in the Xxe2x80x94Mnxe2x80x94Xxe2x80x2 alloy is within the range of 50 to 56% by atomic ratio in the present invention.
It is preferable in the present invention that the antiferromagnetic layer is formed of the Xxe2x80x94Mn alloy (wherein X is either one or two or more of the elements of Pt, Pd, Ir, Rh, Ru and Os), the antiferromagnetic layer being formed under the ferromagnetic layer with the preferable composition ratio of X in the Xxe2x80x94Mn alloy of within the range of 44 to 57% by atomic ratio.
It is preferable in the present invention that the antiferromagnetic layer is formed of the Xxe2x80x94Mnxe2x80x94Xxe2x80x2 alloy (wherein X is either one or two or more of the elements of Pt, Pd, Ir, Rh, Ru and Os and Xxe2x80x2 is one or two or more kinds of the elements of Ne, Ar, Kr, Xe, Be, B, C, N, Mg, Al, Si, P, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ag, Cd, Ir, Sn, Hf, Ta, W, Re, Au, Pb and rare earth elements), the antiferromagnetic layer being formed under the ferromagnetic layer and the composition ratio of X+Xxe2x80x2 in the Xxe2x80x94Mnxe2x80x94Xxe2x80x2 alloy being within the range of 44 to 57% by atomic ratio.
It is preferable in the present invention that the composition ratio of X in the Xxe2x80x94Mn alloy or the composition ratio of X+Xxe2x80x2 in the Xxe2x80x94Mnxe2x80x94Xxe2x80x2 alloy is within the range of 46 to 55% by atomic ratio.
The exchange coupling film produced by the method as described above can be used for a variety of magnetoresistive element.
Firstly, the single spin-valve type thin film element according to the present invention has an antiferromagnetic layer, a pinned magnetic layer formed in direct contact with this antiferromagnetic layer in which the magnetization direction is fixed by an exchange anisotropic magnetic field with the antiferromagnetic layer, a free magnetic layer formed over or under the pinned magnetic layer via a non-magnetic conductive layer, a bias layer for aligning the magnetization direction of the free magnetic layer along the direction to cross with the magnetization direction of the pinned magnetic layer and a conductive layer for imparting a sensing current to the pinned magnetic layer and non-magnetic conductive layer, wherein the antiferromagnetic layer and pinned magnetic layer formed in direct contact with this antiferromagnetic layer are formed of the exchange coupling film described above.
In the present invention, the antiferromagnetic layer is formed on the top or bottom sides of the free magnetic layer of the single spin-valve type thin film element with a space apart by a track width Tw, and the antiferromagnetic layer and free magnetic layer may be formed of the exchange coupling film as described previously.
Secondly, the dual spin-valve type thin film element according to the present invention has non-magnetic conductive layers formed on the top and bottom faces of the free magnetic layer, pinned magnetic layers being situated on the top face of one of the non-magnetic conductive layer and under the bottom face of the other non-magnetic conductive layer, antiferromagnetic layers being situated on the top face of one of the pinned magnetic layer and on the bottom face of the other pinned magnetic layer to fix magnetization directions of respective pinned magnetic layers along a prescribed direction by an exchange anisotropic magnetic field, and a bias layer for aligning the magnetization direction of the free magnetic layer along the direction to cross with the magnetization direction of the pinned magnetic layer, the antiferromagnetic layer and the pinned magnetic layer formed in direct contact with this antiferromagnetic layer being formed of the exchange coupling film described above.
The AMR element according to the present invention has a magnetoresistive layer and a soft magnetic layer laminated via a non-magnetic layer, wherein an antiferromagnetic layer is formed on the top or bottom side of the magnetoresistive layer with a space apart by a tack width Tw, the antiferromagnetic layer and magnetoresistive layer being formed of the exchange coupling film described above.
Shield layers are formed on the top and bottom faces of the foregoing magnetoresistive element via gap layers in the magnetic head according to the present invention.
The interface structure between the antiferromagnetic layer and ferromagnetic layer is made to be non-coherent in the present invention to obtain a proper exchange anisotropic magnetic field when an antiferromagnetic material containing at least the element X (wherein X is either one or two or more kinds of the elements of Pt, Pd, Ir, Rh, Ru and Os) and Mn is used for the antiferromagnetic layer.
The interface structure between the antiferromagnetic layer and the ferromagnetic layer is made non-coherent in order to transform the crystal structure of the antiferromagnetic layer from the disordered lattice to the ordered lattice after subjecting the layers to a heat treatment, thereby allowing a larger exchange anisotropic magnetic field to generate. The relation between the non-coherency and exchange anisotropic magnetic field will be discussed in detail hereinafter.
While the non-coherency means that atoms at the antiferromagnetic layer side and at the ferromagnetic layer side do not show 1 to 1 correspondence at the interface between the antiferromagnetic layer and ferromagnetic layer with different positional relations of respective atoms, it is necessary to properly control the lattice constant before the heat treatment for making the interface structure non-coherent.
The antiferromagnetic layer is formed, for example, of the Xxe2x80x94Mn alloy (wherein X is either one or two or more of the elements of Pt, Pd, Ir, Rh, Ru and Os).
The difference between the lattice constant of the Xxe2x80x94Mn alloy and the lattice constant of the ferromagnetic layer (for example the NiFe alloy) before the heat treatment is adjusted to be large in the present invention by properly selecting the composition ratio of X in the Xxe2x80x94Mn alloy.
Although both of the crystal structure of the Xxe2x80x94Mn alloy in the deposition step (before the heat treatment) and the crystal structure of the ferromagnetic layer assumes a face-centered tetragonal lattice (referred to a disordered lattice hereinafter) in which X and Mn atoms are distributed at random, the interface structure between the Xxe2x80x94Mn alloy in the deposition step (before the heat treatment) and ferromagnetic layer are liable to be non-coherent since the difference between the lattice constant of the Xxe2x80x94Mn alloy and the lattice constant of the ferromagnetic layer are adjusted to be large in the present invention as described previously.
As hitherto described, the interface between the antiferromagnetic layer and ferromagnetic layer is made to be non-coherent by virtue of a proper selection of the composition ratio of the element X in using the Xxe2x80x94Mn alloy (X is, for example, Pt or Pd) as an antiferromagnetic layer. However, the lattice constant of the antiferromagnetic layer can be enlarged by allowing an element Xxe2x80x2 such as a rare gas element (for example Ne or Ar) to contain in the Xxe2x80x94Mn alloy in the present invention, making it possible to set the interface structure between the antiferromagnetic layer and ferromagnetic layer to be non-coherent.
It is preferable in the present invention that the crystal orientation of the Xxe2x80x94Mn alloy or Xxe2x80x94Mnxe2x80x94Xxe2x80x2 alloy is different from that of the ferromagnetic layer. The degree of the crystal orientation may be possibly changed depending on the presence of underlayers, composition ratio, conditions such as electric voltage and gas pressure during sputtering deposition, or the lamination order of the films.
The crystal orientation of the Xxe2x80x94Mn alloy or Xxe2x80x94Mnxe2x80x94Xxe2x80x2 alloy is made to be different from the crystal orientation of the ferromagnetic layer because, for example, when the {111} plane of the ferromagnetic layer is preferentially oriented along the direction parallel to the film surface and the {111} plane of the Xxe2x80x94Mn alloy or Xxe2x80x94Mnxe2x80x94Xxe2x80x2 alloy is also preferentially oriented along the direction parallel to the film surface, non-coherence of the crystal structure can not be valid.
Accordingly, the degree of orientation of the {111} plane of the Xxe2x80x94Mn alloy or Xxe2x80x94Mnxe2x80x94Xxe2x80x2 alloy is properly controlled to be smaller than the degree of orientation of the ferromagnetic layer or to be non-oriented when, for example, the {111} plane of the ferromagnetic layer is preferentially oriented along the direction parallel to the interface between the antiferromagnetic layer and the Xxe2x80x94Mn alloy or Xxe2x80x94Mnxe2x80x94Xxe2x80x2 alloy, thereby making it possible to keep the non-coherency of the interface structure.
As hitherto described, the exchange anisotropic magnetic field is generated at the interface between the Xxe2x80x94Mn alloy or Xxe2x80x94Mnxe2x80x94Xxe2x80x2 alloy and the ferromagnetic layer by applying a heat treatment after laminating the Xxe2x80x94Mn alloy or Xxe2x80x94Mnxe2x80x94Xxe2x80x2 alloy with the ferromagnetic layer so that the interface structure assumes a non-coherent state. Generation of this exchange anisotropic magnetic field is ascribed to transformation of the crystal structure of the Xxe2x80x94Mn alloy or Xxe2x80x94Mnxe2x80x94Xxe2x80x2 alloy from the disordered phase to the face-centered tetragonal lattice in which X and Mn atoms are aligned with an order.
The face-centered tetragonal lattice defined in the present invention refers to so called L10 type face-centered tetragonal lattice (referred to the ordered lattice hereinafter) in which the centers of the four planes among the six planes of the unit lattice are occupied by the X atoms while the corners of the unit lattice and the centers of the top and bottom planes are occupied by the Mn atoms. It is required that at least a part of the crystal structure of the Xxe2x80x94Mn alloy or Xxe2x80x94Mnxe2x80x94Xxe2x80x2 alloy after the heat treatment assumes the ordered lattice described above.
While the exchange anisotropic magnetic field is generated as a result of modification of the crystal structure of the Xxe2x80x94Mn alloy or Xxe2x80x94Mnxe2x80x94Xxe2x80x2 alloy from the disordered lattice to the ordered lattice by applying the heat treatment as hitherto described, the lattice distortion accompanied by this modification becomes larger in the Xxe2x80x94Mn alloy or Xxe2x80x94Mnxe2x80x94Xxe2x80x2 alloy than in the NiMn alloy.
The interface structure between the Xxe2x80x94Mn alloy or Xxe2x80x94Mnxe2x80x94Xxe2x80x2 alloy and the ferromagnetic alloy before the heat treatment can be made to be non-coherent in the present invention by optimizing the composition ratio in the Xxe2x80x94Mn alloy or by adding an element Xxe2x80x2 as a third element to the Xxe2x80x94Mn alloy.
When the interface structure between the antiferromagnetic layer and ferromagnetic layer is non-coherent, the crystal structure of the Xxe2x80x94Mn alloy or Xxe2x80x94Mnxe2x80x94Xxe2x80x2 alloy is liable to be transformed by applying a heat treatment from the disordered lattice to the ordered lattice, thereby generating a large exchange anisotropic magnetic field at the interface.
The Xxe2x80x94Mn alloy (X=Pt, Pd and the like) or Xxe2x80x94Mnxe2x80x94Xxe2x80x2 alloy (X=Ne, Ar and the like) has excellent characteristics as an antiferromagnetic material with respect to superior corrosion resistance to the FeMn alloy or NiMn alloy as well as higher blocking temperature and larger exchange anisotropic magnetic field (Hex) than the FeMn alloy.
It is preferable in the present invention to select Pt for the element X constituting the Xxe2x80x94Mn alloy or Xxe2x80x94Mnxe2x80x94Xxe2x80x2 alloy.
As hitherto described in detail, the exchange coupling film composed of an antiferromagnetic layer formed of the Xxe2x80x94Mn alloy or Xxe2x80x94Mnxe2x80x94Xxe2x80x2 alloy and a ferromagnetic layer can be applied for the magnetoresistive element.
The antiferromagnetic layer and pinned magnetic layer made of a single spin-valve type thin film element and dual spin-valve type thin film element are formed of the exchange coupling film as, for example, the magnetoresistive element in the present invention.
The construction described above enables to tightly fix magnetization of the pinned magnetic layer along the prescribed direction, making it possible to obtain good reproduction characteristics as compared with the conventional elements.
In aligning the magnetization direction in the free magnetic layer of the single spin-valve type thin film element or the magnetoresistive element layer of the AMR element, for example, the exchange bias layer and free magnetic layer, or the exchange bias layer and the magnetoresistive layer may be formed of the exchange coupling film described above.
The construction above makes it possible to properly aligned the magnetization of the free magnetic layer and magnetoresistive layer, thus making it possible to realize good reproduction characteristics.